Here are some examples:
* "The cat sat on the mat under the table." ("on the mat" and "under the table" are both prepositional phrases)
* "I went to the store for milk and bread." ("to the store" and "for milk and bread" are both prepositional phrases)
* "He walked through the park with his dog." ("through the park" and "with his dog" are both prepositional phrases)
Prepositional phrases always consist of a preposition followed by its object (a noun or pronoun). They can function as adjectives (describing nouns) or adverbs (describing verbs, adjectives, or other adverbs).
Let me know if you'd like more examples or have any other questions!